20633

Appears in sequences

• Composite numbers generated by the Euler polynomial x^2 + x + 41.at n=27A145292
• Prime-generating polynomial: a(n) = 16*n^2 - 292*n + 1373.at n=45A181969
• Wiener index of a benzenoid consisting of a chain of n hexagons characterized by the encoding s = 1133 (see the Gutman et al. reference, Sec. 5).at n=15A193399
• Number of nX3 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 0,0,1,1,1 for x=0,1,2,3,4.at n=9A197245
• Semiprimes generated by the Euler polynomial x^2 + x + 41.at n=27A228183
• Number of (n+1) X (2+1) 0..2 arrays with no element unequal to a strict majority of its horizontal and vertical neighbors, with values 0..2 introduced in row major order.at n=9A231213
• Numbers n for which the numbers 6n+1, 3n+2, 6n+7 are all odd composite squarefree numbers, but none are semiprimes.at n=35A263510
• a(n) = Sum_{k=1..n} gcd(k,n)^(n/gcd(k,n)).at n=21A342424
• Numbers k for which A276085(k) is a multiple of 3125, where A276085 is fully additive with a(p) = p#/p.at n=7A377878